The purpose of this study is to test the safety and efficacy of enzyme (recombinant human a-L-iduronidase) replacement in patients with mucopolysaccharidosis I (MPS I). This multi-center clinical study (phase II-III) is directed by Dr. Emil Kakkis, who recruited the patients and directs the enyzme production in the Iduronidase Production Laboratory, Torrance, CA. BioMarin Pharmaceutical, Inc. have been assigned the Investigational New Drug Application number BB-IND #7334 for the enzyme to be used in this study. I have been asked to administer at UNC some of the enyzme infusions to two patients with MPS I. Preliminary results have indicated that the enzyme infusions have been beneficial to the patients. Benefits have included decreased liver and spleen size, decreased pain, increased exercise tolerance with decreased joint stiffness, improved gait with better balance, improved vision and hearing.